Jet deflecting apparatus



Dec. 15, 1959 N. K. WALKER JET DEFLECTING APPARATUS Filed Oct. 22, 1958 INVENTOR. formula!- Walker E ATTORNEYS U d States P m 2,916,873 JET DEFLECTING APPARATUS Norman K. Walker, Kcnsington, Md., assignor to Adtfigced Research Associates, Incorporated, Kensington,

Application October 22, 1958, Serial No. 768,902 4 Claims. (Cl. 60-3554) ing across a nozzle has a natural tendency to separate from the sides of the nozzle in the divergence region thereof. This separation may set up eddy currents along the sides of the nozzle. This is usually prevented by shaping and designing the nozzle carefully, keeping the flow passages smooth, keeping tively small. If gas or vaporized fluid is injected in the regionof the expanding nozzle just downstream from the throat, it will trigger a separation of the flow from the same side of the nozzle downstream thereof. Hence, the flow will stream back from the side of the nozzle downstream from the injection and the whole exiting jet may be effectively deflected by the injection of a small quantity of gas. This deflecting eflect may be promoted such that large deflections are obtained for small quantities of injected fluid by shaping the nozzle such that separation is more easily achieved but will still not .occur unless triggered by the injected fluid. This implies that the divergence angle in the region of the secondary flow after injection must be somewhat greater than the normal design.

Several means have been proposed in the prior art for controlling the direction of a jet and one known means for accomplishing this result is the injection of compressed air by means of an auxiliary nozzle positioned to inject the air at a substantial axis to the angle of the jet. For the control of a good sized jet it is necessary to inject a considerable amount of compressed air as well as provide a source ofcompressed air and relatively large air-handling valves and specially designed nozzles. Some of these problems can be avoided by draining hot gases from the high-pressure gas flow upstream of the nozzle but in this case the secondary flow passages and controlling means must be capable of handling extremely hot gases. It is the object of this inventionto provide a jet deflecting arrangement whereinthe injected jet deflecting fluid may be easily and readily handled as a liquid and this fluid may be injected without the aid of a specially designed nozzle. The heat of the jet will cause the liquid to vaporize after it has passed through the controlling means and the vapor is utilized to deflect the jet.

It is also an object of this invention to provide a jet deflection means utilizing an injected and easily controllable liquid for controlling the jet deflection and further utilizing pressure upstream of the jet for supplying the motive power for injecting the liquid.

Other objects and advantages of this invention will be the divergence angle relaapparent from the following detailed description and claims taken in connection with the accompanying drawing, which discloses, by way of example, the principles of this invention and the best mode which has been contemplated of applying these principles.

In the drawing:

Fig. 1 is a schematic side elevation view, partially in section, showing the jet deflection means of this invention: 1 a i Fig. 2 is a schematic sectional view taken generally along the section line 2-2 of Fig. 1;

Fig. 3 is a schematic illustration of a poorly designed nozzle showing jet separation from the sides of the divergent portion thereof;

. Fig. 4 is a schematic illustration of an eflicient nozzle with separation prevented by the correct design and narrower divergence angle; and

Fig. 5 is a schematic illustration of a nozzle provided with auxiliary fluid injection for triggering jet separation and accomplishing jet deflection.

In general, this invention contemplates providing a jet deflection means in the nature of at least one injecting means for selectively injecting a fluid downstream from the throat of the jet forming nozzle. The auxiliary injection fluid is a vaporized liquid which is vaporized by the heat of the hot jet. Suitable liquid control valves may :be provided for controlling the fluid injection and the pressure for injecting the liquid is obtained upstream from the jet nozzle.

. Referring to the drawing, a reaction propulsion motor 10 includes a nozzle 12 for forming a jet 14 of high temperature fiuid'eXiting therefrom. This high temperature fluid may be the products of combustion produced in a combustion chamber 16.

' The principles utilized in the jet deflection apparatus.

rect design such that the jet exiting from a nozzle as shown in Fig. 4 with a fine divergence angle will not have any eddy currents or turbulence along the sides thereof. This invention utilizes these known principles by providing a nozzle designed as shown in Fig. 5 where-' in the divergence angle is just enough to provide a very slight tendency for eddy currents to form along the sides thereof such that when an auxiliary fluid is injected downstream from the throat of the nozzle at a low velocity this separation is promoted or triggered on that portion of the side of the nozzle downstream from the auxiliary injection. This intercepts the streamlined flow of the jet along this side of the nozzle and causes the entire jet to effectively deflect.

To control the direction of the jet 14,suitable injecting means are provided. These means are shown as vaporized liquid injectors 18 and 26 suitably insulated by insulation 20 such that the liquid therein will not vaporize until it has passed through a control valve 24. A

fluid line 22 connects the injectors with the control valve 24. Control valve 24 selectively controls the injection of vaporized liquid from both injectors 18 and 26 which may be positioned opposite each other as shown in Fig. 2. It is apparent that some small amount of liquid as well as the liquid vapor may be injected from injectors 18 and 26, however, any liquid will be immediately vaporized after injection to accomplish the jet breakaway from the nozzle side Walls and the jet deflection in the same manner that the injected vaporized liquid will cause jet breakaway and thereby jet deflection.

Pressure for injecting from injectors 18 and 26 is Patented Dec. 15, 1959.

obtained by establishing fluid communication upstream of the nozzle 12, between the combustion chamber 16 and a liquid tube 28. In the preferred embodiment the pressure of the combustion chamber 16 is transmitted directly to the liquid in tube 28, although it would be obvious to insert an intermediate pressure-transmitting member such as a slidable piston or the like. Tube 28 may have a plurality of loops 30 therein for holding a suitable amount of liquid to be injected. Alternatively, tube 28 may connect with a closed reservoir containing the liquid to be injected. As is well known in the art, a high length-diameter ratio, as provided by tube 28 shown in the drawing, will prevent combustion gases from working through the liquid more than a few diameters of the length of the tube even during great disturbances encountered in the operating environments of reaction propulsion motors.

The liquid injected may be water, or other suitable liquid if corrosion problems are existent, and at the high temperature of the jet the liquid will vaporize downstream of valve 24 and this vapor will accomplish the jet deflecting function as described above. Therefore, the control valve 24 may allow the liquid to be injected either from injector 18 or from injector 26 and thus may be used for steering the motor. Since the valve 24 controls liquid flow in relatively small liquid tubes it may also be small and susceptible to accurate control.

The tube 28 is filled with a liquid by any conventional means prior to operation of the motor and the ends of the tube 28 may be closed with small blowout plugs as are well known in the art. When the motor is started these plugs will pop out. If the motor is standing vertically and valve 24 is closed, there is no need for blowout plugs after the tube 28 is filled with liquid above the closed valve 24.

Although only two liquid injectors l8 and 26 are shown, it is of course obvious that these may be multiplied to any desired number. Also, although the described embodiment is especially applicable to rocket propulsion, it can also be utilized in deflecting the jet of a jet engine.

While there has been shown and described the fundamental novel features of this invention as applied to the preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only by the scope of the following claims and reasonable equivalents thereof.

I claim:

1. In combination with a nozzle having a throat and divergent side walls for forming a jet of high temperature gas flowing generally axially therethrough, a jet deflecting apparatus comprising; injecting means for injecting a vaporized liquid at low velocity into the nozzle downstream from the nozzle throat, a liquid flow controlling means, a conduit connecting the liquid flow controlling means and the injecting means, means for supplying a liquid under pressure to said liquid controlling means, the heat of the gaseous jet exiting from said nozzle being suflicient to vaporize the liquid supplied by said liquid supplying means through said fluid controlling means only downstream of the liquid flow controlling means and the heat of the gaseous jet exiting from the nozzle being suflicient to at least partially vaporize the liquid in said conduit upstream from said injecting means, and the low velocity injected'vaporized liquid causing jet breakaway from the nozzle side walls to thereby accomplish a jet deflecting function.

2. An apparatus for controlling the thrust direction of a jet of a reaction propulsion motor, said apparatus comprising; a reaction propulsion motor having a nozzle with a throat and diverging side walls forming an exit jet for propelling gas, said gas being at a temperature suflicient- 1y high to immediately vaporize a suitable controlling liquid, injecting means for injecting the controlling vaporized liquid into the jet at low velocity to cause jet breakaway from the nozzle side Walls to thereby deflect the jet, and liquid control means for controlling the application of liquid to the injecting means.

3. An apparatus for deflecting a jet of high temperature gas exiting from a nozzle having a throat and diverging side walls for forming a jet, said apparatus comprising; injecting means for injecting a vaporized liquid downstream of the throat of said nozzle, the injection being at a low velocity for causing jet separation from the side walls of the nozzle downstream of the injected fluid, a source of liquid supply, valve means controlling application of liquid from the source of liquid supply to the injecting means, the liquid being easily controlled by the valve means and being vaporized by the high temperature of the jet between the injecting means and the valve means.

4. An apparatus for steering a rocket motor, the rocket motor having a combustion chamber containing combustion gases at high pressure and an exit nozzle with diverging side walls for forming a jet of high temperature gas, said apparatus comprising; a liquid-carrying conduit having one end in fluid communication with said high-pressure combustion chamber and the other end in fluid communication with the jet downstream of the nozzle throat in at least one portion of the nozzle side walls for vaporized liquid injection, said conduit having a high length-diameter ratio, a valve in said conduit for controlling the flow of liquid therethrough, the heat of the jet acting to vaporize the liquid in the conduit between the valve and the nozzle side walls and the pressure of the combustion chamber acting to force the vaporized liquid into the jet downstream of the nozzle at a low velocity to cause jet breakaway and thereby cause jet deflection for steering.

References Cited in the file of this patent UNITED STATES PATENTS 916,726 Lake Mar. 30, 1909 2,434,298 Truax Jan. 13, 1948 2,728,191 Casey Dec. 27, 1955 2,763,983 Kafka Sept. 25, 1956 2,865,170 Kadosch Dec. 23, 1958 FOREIGN PATENTS 1,057,271 France Oct. 28, 1953 1,130,132 France Sept. 17, 1956 357,797 Germany Sept. 1, 1922 565,952 Great Britain May 26, 1943 795,652 Great Britain May 28, 1958 

